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Re: Property Path Profiles

From: Andy Seaborne <andy.seaborne@talis.com>
Date: Tue, 12 Jan 2010 09:03:13 +0000
Message-ID: <4B4C3AD1.3000308@talis.com>
To: matthew.perry@oracle.com
CC: Ivan Herman <ivan@w3.org>, W3C SPARQL Working Group <public-rdf-dawg@w3.org>
I don't understand the restriction to one unbounded path component.

Looking at:

{ :v1 :myProp1*/:myProp2+/:myProp3? :v2 }

It is the same as:

{ :v1 :myProp1* ?x1 .
   ?x2 :myProp2+ ?x3 .
   ?x3 :myProp3? :v2 }

Matt - What is the key difference between the supported and unsupported 
examples?

	Andy


On 11/01/2010 7:12 PM, Matt Perry wrote:
> Hi Ivan,
>
> Basically, combinations of complex paths are not supported.
>
> For example, { :v1 :myProp1* :v2 }, { :v1 :myProp2+ :v2 }, and { :v1
> :myProp3? :v2 } are all supported, but { :v1
> :myProp1*/:myProp2+/:myProp3? :v2 } is not supported.
>
> Hope this helps,
> -Matt
>
> Ivan Herman wrote:
>> Matt,
>>
>> to make things more understandable (for me:-) can you summarize what are
>> the features in the current property path document[1] that are _not_
>> covered? Ie, what do we give up if we use such profile(s)?
>>
>> Thanks for your help
>>
>> Ivan
>>
>> [1]http://www.w3.org/2009/sparql/docs/property-paths/Overview.xml
>>
>> On 2010-1-11 19:25 , Matt Perry wrote:
>>
>>> Hi,
>>>
>>> During the last TC, I mentioned the possibility of a Property Paths
>>> profile that identifies a subset of property path queries that can be
>>> expressed with SQL. Such a profile would make it easy for triple stores
>>> implemented on top of relational databases to identify the set of
>>> property path queries that they "natively" support.  The purpose of this
>>> email is to start a discussion about the possibility of property path
>>> profiles.
>>>
>>> The grammars below show two possible fragments that we have identified.
>>> The first grammar is for SQL + CONNECT BY (Oracle) and the second is for
>>> PLAIN SQL.
>>>
>>> CONNECT BY:
>>>
>>> ALT  ->  URI | URI|ALT
>>> SEQ  ->  URI | URI/SEQ
>>> Elem ->  URI | SEQ   | ALT   | ^URI
>>> COMP ->  URI | Elem* | Elem+ | Elem{n,m} | Elem?
>>> TOP  ->  URI | COMP  | ALT   | SEQ       | ^URI
>>>
>>> PLAIN SQL:
>>>
>>> ALT  ->  URI | URI|ALT
>>> SEQ  ->  URI | URI/SEQ
>>> Elem ->  URI | SEQ       | ALT   | ^URI
>>> COMP ->  URI | Elem{n,m} | Elem?
>>> TOP  ->  URI | COMP      | ALT   | SEQ   | ^URI
>>>
>>> Thanks,
>>> Matt
>>>
>>>
>>>
>>>
>>
>>
>
>
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Received on Tuesday, 12 January 2010 09:03:52 GMT

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